EP2560756B1 - Device for plasma separation by means of a central channel structure - Google Patents

Description

The invention relates to a device for filtering a fluid and for discharging the filtered fluid, in particular plasma into a diagnostic test cartridge.

The prior art is formed by filtration apparatus for the separation of blood plasma. That's how it shows US 2009/0120865 A1 a corresponding multi-layer disposable device, which is attached to a biochip. The filtration device comprises, stacked and interconnected, an upper substrate having a blood inlet, a middle substrate having the filter unit for separating the plasma from the blood, and a lower substrate having an air outlet. In the filter unit is located (in a filter chamber) of the actual filter on two sealing rings, one of which releases an opening in a likewise arranged in the middle substrate micro-channel with subsequent micro chamber.

The WO 2009/112982 A1 shows a filtration device with a filter element and an attached thereto (eg in the form of a double-sided adhesive tape) adhesive capillary structure through which the filtered fluid is passed from the filter to a detection point. The capillary structure in this case is a microfluidic structure which generates capillary forces and covers at least 25% of the lower surface of the filter element.

The US 2007/269893 A1 shows a device for collecting blood and for separating blood plasma as a liquid sample, wherein a channel absorbs the liquid sample by the use of capillary forces. For uniform filling takes place directly below the separating device ventilation in the transverse direction to the main filling direction in the vicinity of the channel.

The invention finds use in microfluidic devices which are used for fluid separation, in particular blood separation.

In the separation of particles from a fluid, such as a blood separation, the medium to be separated, in this case blood, is placed on a filter. The fluid and small components flow through the filter and are transported away via channels in the device. In order to detect certain properties of the fluid, the fluid is brought into contact with reagents which cause a chemically or physically detectable interaction, eg a discoloration of the fluid in a detection reaction.

For these various wet-chemical, biochemical or diagnostic analyzes, it is necessary for the fluid to mix with and release reagents in a chamber or reservoir for a defined time interval and / or react with them.

The reagents can be bound to a chamber, a channel or a reservoir wall or to particle surfaces.

In immunochemical analyzes, the reagents are for example antibodies, enzymes, biotinylated proteins and antibodies, streptavidia or phosphatases.

It is necessary in various such dissolution processes or reactions that a given predetermined volumetric flow or mass flow is provided to fluid in a given time interval to achieve safe dissolution of the reagent or a safe reaction.
If the required fluid flow is not reached or torn off, for example, there is a risk that components of a dried, in particular pulverulent, substance arranged in the microfluidic analysis device may clump or adhere to depots. This can lead to the result of a detection reaction being falsified.

Even in applications where several chambers are to be filled in parallel or sequentially, a sufficient fluid flow for homogeneous filling of the chambers is required.

Critical to the provision of a homogeneous fluid supply in detection chambers is, for example, an inclusion of air bubbles in the separation region or in the region of the channel inlet of a fluid-discharging channel, since trapped air bubbles reduce the volume flow or can completely tear it off.

Against this background, the object of the invention is to provide a predetermined amount of fluid to be examined in a predetermined time interval in an examination area.

Furthermore, the object of the invention is to constructively design a microfluidic device such that a reliable supply of the separated fluid from the input area to the analysis area takes place.

Since adhesive layers and also some plastics, as typically used in microfluidic cartridges, are hydrophobic, they can prevent or hinder the entry of aqueous liquids into a feed channel.

Against this background, the invention has the further object of designing the capillary aperture of a Fluidabführkanals constructive and / or functional so that a secure wetting of the discharge channel is achieved, that is, it must be ensured that the separated liquid can be absorbed by the discharge channel and can be removed from this.

From the EP 1548433 A1 a separation device is known in which the liquid to be separated is passed through a feed opening onto a separation membrane and the filtering process takes place in the thickness direction of the membrane. The filtered fluid is taken up in a filling chamber and discharged through capillary channels.

A disadvantage of this arrangement is the high dead volume of the filling chamber and the risk that air in the chamber is not homogeneously displaced by the fluid, but forms air bubbles in the fluid, which hinder the flow of fluid.

Dead volume is understood to mean that volume of the fluidic channel structures and chambers which does not act as a reaction volume. Since the filling chamber after the EP 1548433 A1 must first be completely filled and fluid remains in the chamber, the chamber volume of the filling chamber is thus dead volume.

The EP 1 054 805 B1 describes a method to fill a microfluidic network from a central sample application having a capillary active opening area. To remove the sample from the sample task, which is designed in the form of an inlet chamber, a feed channel opens into a wall of the chamber. In order to improve the capillary sample intake through the feed channel, the capillary aperture of the feed channel is increased by fluidically connecting a circumferential capillary channel open to the inlet chamber to the feed channel.
If a liquid comes into contact with this capillary channel or gap, the liquid automatically capillates into the microfluidic network, provided that the contact angle of the liquid with the substrate and the viscosity of the liquid are not too high.

A disadvantage of this arrangement is again an increased dead volume of the arrangement, since separated sample liquid can be retained by the circulating capillary channel.

Against this background, the further object of the invention is to provide an improved separation device with reduced dead volume.

These objects are achieved according to the invention by a microfluidic device having the features of claim 1.

The microfluidic separation device according to the invention makes it possible to provide a sufficient volume flow of fluid. For this purpose, the device has a means for separation, in particular blood filtering and comprises a discharge channel which receives and discharges the separated fluid. The device according to the invention makes it possible to fill a microfluidic network and / or a chamber from a discharge channel with a smaller active capillary cross-section or a smaller opening aperture. In addition, the dead volume of a feed device and / or separation device can be reduced to a minimum by means of the described method.

In microfluidic cartridges, the microfluidic network is usually formed in a plate-shaped substrate. For this purpose, a moldable plastic such as polystyrene (PS), polymethylmethacrylate (PMMA), polycarbonate (PC), olefin polymers and olefin copolymers such as cycloolefin polymer and Cylcoolefincopolymer (COC and COP), polyamide (PA), polypropylene (PP), polyethylene (PE) or Polyethyletherketone (PEEK) injected in a negative mold.

The channel structures are closed by a foil which is arranged on the substrate.

The film thereby covers the channel and / or chamber structures formed in one or both sides of the plate, thereby forming a microfluidic channel system having feature widths and feature heights of a few tens of microns to a few millimeters. The film covers the plate-shaped component partially or completely.

The film can be multi-layered. In particular, the film may be provided on one or both sides with an adhesive layer for attachment to the plate-shaped substrate. The adhesive layer is preferably a low-melting laminating layer or sealing layer of ethylene-vinyl acetate copolymer (EVA). Alternatively it can be provided as an adhesive layer and an acrylate adhesive.

The surface and / or the channel structures may have been subjected to surface treatment and / or surface coating over the entire area or part of the area.
As a surface treatment / surface activation, for example, a plasma irradiation / plasma etching, gamma irradiation or UV irradiation to improve the surface adhesion may be carried out.
For example, a hydrophilization or hydrophobization of the channel regions for improved fluid conduction and / or fluid control of aqueous fluids is conceivable as surface coatings.

Alternatively, the film can also have an additional sealing layer, which is welded onto the surface of the substrate in a hot lamination process.

Furthermore, the film can be laminated directly, that is, it is created without the melting of a sealing layer by pressure and heat a cohesive connection between the film and the substrate. The lamination may also be cold, with the preferred use of an acrylate adhesive layer.

Preferably, the film is flat. However, it can also be provided to mold the film locally, for example to form deformable chambers, or to mold in order to form pressure- or vacuum-controlled valves and microactuators.

In addition to a first film, a second film may be arranged on the plate-shaped substrate and / or the first film. The second film may have further microfluidic structures such as channels, chambers and / or openings. The second film preferably comprises structures for a biosensor, in particular measuring means such as electrical contacts and / or electrical potential surfaces and / or optical structures such as optical light guides and / or optical mirror surfaces.

To operate the microfluidic cartridge in, for example, an analyzer, an amount of fluid is introduced into a feeder. This may be, for example, a blood drop of 5 to 50 microliters volume, for lateral flow tests preferably 5 to 100 microliters.

The feeder is in the simple case a filling opening. The feeder may further comprise other components. For example, the feeder may be a funnel-shaped insert that is inserted into a fill port to facilitate the blood application and expand the input space. The supply device may also comprise a finger recess, which surrounds a filling opening and serves as a support surface and / or positioning surface of a patient's finger in the blood addition.

This trough is preferably introduced into a plate-shaped cover element. The cover element then forms the feed device.

The device according to the invention for sample separation further comprises a separating device with a means for separating and / or separating and / or filtering sample components.

The means for separating and / or separating and / or filtering is advantageously a membrane or a filter to which the sample liquid is supplied and wherein the liquid flows through the membrane and / or filter and sample components are retained by the filter or the membrane.

Flow through the filter is through pores and / or capillaries that form a fluid-open network through the filter. Advantageously, a filter made of glass fiber, polysulfone or polyethersulfone is used.

In order to separate blood plasma from a blood sample, it is preferred to use a filter having an average pore size of from... To... Micrometers. Advantageously, the filter is in
an upper plate-shaped substrate welded in the filling opening. This cover element preferably has a recess at the filling opening, in which the filter, in particular a membrane can be inserted. Particularly preferably, the membrane is welded to a surface of the recess, the attachment surface.

The fluid flow is transported in particular in the vertical flow direction through the membrane or the filter.
This vertical direction indication means that the flow is approximately perpendicular to the substrate plane of a particular plate-shaped microfluidic metering device.

The flow thus flows through a membrane substantially in the thickness direction.

The membrane or filter is preferably arranged in the vertical direction between the inlet opening and an inlet chamber or collecting chamber located below the membrane / filter.

The membrane or filter absorbs liquid through the capillary action of its pores or capillaries and retains larger particles whose size exceeds those of the pores or capillaries.

In the process, the pores partially close due to agglomeration of the retained particles, so that the available flow cross section with Andauer reduced the progressive separation process. This causes a decrease in the flow rate of the volume flow of fluid in the microfluidic device.

At the separator, an inlet chamber or collection chamber is arranged, in which flows the separated sample liquid.

The inlet chamber or collecting chamber is understood to mean the space in the fluidic device for sample separation, into which the separated sample liquid directly enters after passing through the separating device, in particular after flowing through a filter or a membrane.

The inlet chamber or collection chamber may be a channel and / or a chamber located directly below a membrane and open at the top, so that the separated sample liquid is taken up by the channel and / or the chamber.

Conveniently, the inlet chamber or collection chamber is formed by the space bounded above by the membrane or filter.

The lower filter or membrane surface then forms an upper interface with the inlet or collection chamber.

The space of the inlet chamber is bounded in this embodiment down through the plate-shaped substrate that forms the bottom of the collection chamber.
The sides of the room may be formed by walls and / or more preferably be enclosed by a vent trench, as will be explained below.

The inlet chamber or collection chamber may be completely filled by the membrane or the filter. In this constructive embodiment, the filter or membrane is both part of the separator and part of the inlet or collection chamber.

From the inlet chamber or plenum, one or more venting channels may exit.
Furthermore, the device is structurally designed so that separated sample liquid can be discharged from one or more channels in the lateral direction.

Advantageously, the inlet chamber or collection chamber may contain reagents which are dissolved by the fluid flow.

Likewise, the membrane may also be impregnated or impregnated with reagents, for example reagents glycine or lectin, which promote clumping of the fluid, in particular of the blood, so that larger particle clusters are formed, which are retained by the membrane. Upon addition of the fluid, separation takes place in the membrane treated in this way, with simultaneous dissolution of a first reagent, the first reagent influencing the biological and / or chemical and / or physical properties, in particular the viscosity of the fluid.

In the inlet chamber or collection chamber may be arranged a second reagent which causes a detection reaction in the fluid. This can be, for example, an optical discoloration.

Since the membrane or the filter have a high intrinsic capillarity, means are advantageously provided to assist a vertical flow of the volume flow into the adjacent inlet or collecting chamber. For this purpose, the inlet or collecting chamber advantageously has one or more steles and / or webs and / or ramp-shaped surfaces. These may preferably support or form the one or more vertically extending notches.

The steles and / or webs and / or inclined surfaces are designed so that the membrane rests on these structures. The height of the structures advantageously corresponds to the depth of the inlet or collection chamber, the depth of which is preferably 10 microns to 1000 microns, especially 50 microns to 500 microns.

The notches on the structures or the structures themselves come into fluidic contact with the membrane to be contacted and, by virtue of their capillary action, discharge fluid from the membrane to the bottom of the chamber so that the collection chamber is wetted. Alternatively or supportively it can be provided that the membrane is bulged, wherein the height of the curvature of the chamber depth corresponds, so that the membrane rests on the vertex of the vault on the chamber floor.
Since the apex of the membrane forms an acute angle with the chamber bottom, there occur high capillary forces upon wetting of the membrane, so that fluid separated over the gap between membrane and chamber bottom is discharged into the collection chamber.

Advantageously, the inlet or collecting chamber is at least partially surrounded by a trench, which has a greater depth and a vent compared to the chamber depth, so that the air in the inlet or collecting chamber can be displaced by the inflowing fluid through the trench. The filling trench preferably has a width of at least 100 microns and a depth of at least 5 microns.

The volume of the inlet or collection chamber is preferably 0.01; 0.02; 0.05; 0.1; 0.2; 0.5; 1; 2; 5; 10; 20; 50; 100; 200; 500; 1000 microliters, whereby chamber volumes can be selected, which result from the addition of the indicated values.

The vent trench described above forms a fluid stop, since the fluid flow can not overflow the trench stage. Advantageously, the trench completely encloses the inlet or collection chamber in which the discharge channel extends, except for the outlet region of the inlet or collection chamber, so that the air can be uniformly displaced from the inlet chamber.

In the area between the chamber outlet and the trench ends, which adjoin one another, there is the danger that an undesired outflow of fluid into the trench takes place.
Therefore, it is particularly advantageous to design the sample separation device such that no fluid enters the trench.

This is achieved on the one hand by the fact that the ends of the vent trench are widened. By widening the capillary stage is increased to fill the vent trench, which means that the risk of unwanted filling of the vent trench is significantly reduced.

The inventive embodiment of the separation device provides that the channel for discharging the separated sample liquid from the inlet or collection chamber is arranged in the bottom of the collection chamber, that is, the channel is formed by a recess in the bottom of the inlet chamber.

The term discharge channel is understood to mean a channel which can receive a liquid from the inlet chamber and transfer it into a microfluidic fluid network.

The arrangement of the discharge channel in the bottom of the inlet chamber has the advantage that the separated sample liquid does not first have to completely fill the inlet chamber be removed by a laterally located channel, but a direct removal of the separated sample liquid to analysis areas of the microfluidic cartridge takes place.

This structural design thus avoids the formation of dead volume of sample liquid, which would not be available for analysis.
This is particularly advantageous in those diagnostic applications where only a small amount of sample, such as a 10 to 50 microliter drop of blood corresponding to a separated amount of blood plasma of 5 to 20 microliters in volume, is available.

Furthermore, the discharge channel is advantageously covered in a fluid-tight manner by a film, at least where the channel extends in the vicinity of the venting trench end, so that an undesired fluid connection between the channel and the venting trench is prevented. The discharge channel is also covered in the inlet chamber at least in sections by the film, so that it is achieved that the inflow region for the separated liquid is in the inlet or collection chamber.

This channel cover is designed as a tongue, which closes the channel fluid-tightly approximated to the middle of the inlet or collection chamber, so that a centrally introduced into the filling opening and separated by the membrane sample liquid can flow directly into the central discharge channel.

In a preferred embodiment of the invention, the channel has a means for supporting the capillary wetting of the channel.
This means may advantageously be a notch with increased capillary action connecting the chamber bottom to the bottom of the discharge channel.
As a further alternative means can be arranged at least one ramp between the chamber bottom and the channel bottom, which acts in the same way capillary connecting.

Fig. 1:

eine erste Ausführungsform einer Cartridge (21) mit einer Vorrichtung zur Probenseparation (1)

Fig. 2:

eine zweite Ausführungsform einer Cartridge (21) mit einer Vorrichtung zur Probenseparation (1)

Fig. 3:

eine Ansicht der Cartridge (21) nach Fig. 2 mit Deckelfolie (6)

Fig. 4:

eine Schnittdarstellung der Probenseparation (1) einer Cartridge nach Fig. 2 und Fig. 3

Fig. 5:

eine Schnittdarstellung der Probenseparation (1) einer Cartridge nach Fig. 1

Fig. 6:

eine perspektivische Ansicht der Probenseparation (1) nach den Figuren 2 und 3

Fig. 7 bis Fig. 9:

eine Darstellung eines Querschnittes durch die Probenseparation (1) nach den Fig. 2, 3 und 6 bei Zugabe einer Probenflüssigkeit

The invention will be described in more detail in the following embodiments. It shows

Fig. 1:

A first embodiment of a cartridge (21) with a device for sample separation (1)

Fig. 2:

A second embodiment of a cartridge (21) with a device for sample separation (1)

3:

a view of the cartridge (21) after Fig. 2 with cover foil (6)

4:

a sectional view of the sample separation (1) of a cartridge after Fig. 2 and Fig. 3

Fig. 5:

a sectional view of the sample separation (1) of a cartridge after Fig. 1

Fig. 6:

a perspective view of the sample separation (1) according to the Figures 2 and 3

7 to 9:

a representation of a cross section through the sample separation (1) after the Fig. 2 . 3 and 6 with the addition of a sample liquid

A cartridge (21) with a device according to the invention for sample separation (1) is disclosed in US Pat FIG. 1 shown. In this case, the cartridge (21) is assembled from several components (2, 3, 6). The base of the cartridge (21) forms a lower plate-shaped substrate (2) into which microfluidic structures with structure widths of a few micrometers to several millimeters are formed.

The lower plate-shaped substrate (2) is in particular a plastic plate and in this case comprises a Probenzuführbereich. The sample supply region is in particular an inlet chamber (10) into which a sample liquid to be separated flows after separation.

The inlet chamber (10) is at least partially bounded by a vent trench (7). The vent trench (7) consists of a preferably recessed channel with a width of at least 100 microns and a depth of at least 5 microns. The vent trench (7) forms a capillary stage to the inlet chamber (10) and is vented through vent channels (19) so that liquid entering the inlet chamber displaces the air in the inlet chamber (10) via the trench (7) and channels (19) can and wherein the separated sample liquid itself stops at the edge of the trench (7).

As the lower schematic assembly drawing in FIG. 1 and the FIGS. 7 to 10 show, by welding the membrane (14) in the upper plate-shaped substrate (3) along the mounting surface (18), a circumferential gap (25) which extends both over the feed channel (9) and over the vent trench (7).
The gap or annular channel (25) produced by the edge of the membrane runs coincidentally over the venting trench (7) and is covered by the film (6) at the channel region.

The opening (15) in the film particularly preferably corresponds approximately to the diameter of the membrane (14) in the unattached membrane region, so that the film edge rests circumferentially on the membrane surface. Since very thin films of 20 microns to 200 microns thick are used, which are elastic, the film (6) is stabilized by the overlay on the membrane (14) and prevents unwanted fluid drainage into the gap (25).

Particularly advantageously, the end of the circumferential vent trench (7) of the inlet chamber (10) is widened. This trench widening (13) fulfills the task of preventing fluid drainage from the inlet chamber (10) or the discharge channel (9) into the venting trench (7).

The trench widening (13) helps to reliably prevent unwanted fluid flow from the channel (9) via the gap (25) or from the membrane (14) via the gap (25) in the vent trench (7) by capillary vertical or three-dimensional wetting occurs. The expansion increases the capillary resistance for unwanted capillary wetting of the vent trench, as the distance between said gap (25) and / or the membrane (14) to the bottom of the vent trench is increased.

Alternatively or supportively, it can be advantageously provided that a hydrophobically acting film (6) at least partially covers the venting trench.

The FIGS. 7 to 9 show such a partial overlap of the circumferential vent trench (7) wherein the film (6) extends approximately to the middle of the vent trench (7). This ensures that, on the one hand, the venting function of the trench (7) is maintained, but on the other hand, no aqueous liquid enters the gap (25) or the gap (25) in the venting trench (7), this from the difficultly wettable hydrophobic film ( 6) is pushed back.

Particularly advantageously, the film (6) is designed so that it closes and / or covers the discharge channel (9) in the vicinity of the ends of the vent trench (7) in a fluid-tight manner.

This cover may be a tongue (8) which is integrally connected to the film and projects into an opening (15) in the film (6), as the Figures 2 . 3 . 4 . 6 and 7 schematically represent.

The structure according to the invention according to the first embodiment allows a complete filling of the inlet chamber (10), wherein it is functionally preferred not to completely fill the inlet chamber (10), but to separate separated sample volume directly by means of the discharge channel (9) for further reaction and analysis.

The discharge channel (9) directs the separated sample liquid into a fluidic network, in particular a capillary network consisting of analysis chambers (20) and further components.

In an embodiment according to Fig. 1 at least one, in the exemplary embodiment four analysis chambers (20) are fluidically connected to the channel (9). In this case, the analysis chambers (20) can be filled either sequentially or in parallel.

Thus, a parallel or sequential filling can be done by not shown here active or passive valves for controlling the flow or by a controlled vent.

The analysis chambers (20) are connected by further channels with capillary stops (16). During operation, separated sample liquid first enters an analysis chamber (20), displaces the air trapped in the analysis chamber (20), fills the chamber (20) completely free of air bubbles, and then flows into a first venting channel (22).

The first venting channel (22) is subsequently filled with fluid. By fluid intake of the first venting channel (22) ensures that the analysis chamber (20) is completely filled.

This ensures that no air bubbles remain in an analysis chamber (20). Air bubbles can hinder or distort the diagnostic analysis.

This can be done, for example, if reagents are not dissolved in the analysis chamber, since chamber areas under an air bubble are not wetted.

Furthermore, the complete filling ensures that a defined sample volume, namely the volume of an analysis chamber (20) reacts with the reagents, in particular detection bodies, and thus a qualitative as well as quantitative analysis value can be achieved.

Since the sample liquid in the first venting channels (22) has no contribution to the analysis reaction, ie no useful volume but dead volume, the volume fraction of the first venting channels should amount to a maximum of 5% of the total volume of the analysis chambers (20).

According to the first embodiment according to FIG. 1 it is provided that in each case two first venting channels (22) open into a capillary stop (16), whereby the fluid flow of the sample liquid breaks off there.

Advantageously, the capillary stop (16) is structurally formed in that the venting channel (22) has a smaller cross-sectional area than the capillary stop (16).

The vent channel (22) and the capillary stop (16) share a common boundary surface, namely the upper boundary surface, which is delimited by the underside of the film (6). Typically, film material or the adhesive layer of a film is hydrophobic, so that the capillary flow along the lower side of the film, corresponding to the channel upper side (22), is more difficult.

The capillary stop (16) preferably has a greater depth and a greater width than the first venting channel (22).

As a result, geometrical capillary stages are generated both in the lateral directions and in a vertical direction.

Particularly advantageously, it can be provided that the film (6) at least partially on the capillary stop (16) has recesses, such that at the end of the first vent trench, the capillary stop (16) extends into the film (6).

The Kapillarstop (16) has compared to both side surfaces of the channel (22) so a greater width and compared to the bottom and the ceiling surface of the channel (22) also has a greater depth and a greater height.

As a result, in this particularly preferred embodiment, capillary stages are present both in all lateral directions and in all vertical directions.

The capillary stop (16) is vented through another vent trench (19) which fluidly connects the capillary stop (16) to a side face of the cartridge (21).

The fact that the channel recesses (9) and chamber recesses (20) receive a cover surface through the film, a three-dimensional, full-volume fluid wetting is achieved. To support this, the film (6) and / or the recesses (9, 22, 20) may be at least partially hydrophilized, in particular in the form of a coating by an applied hydrophilic fluid, which is dried.

The film (6) and / or the structures (7, 10, 13, 16, 19) can advantageously also be locally hydrophobized.

In this case, the venting channel (7) and its widening (13) are preferably completely hydrophobicized, so that the capability of capillary wetting of the trench (7) and its widening (13) by an aqueous liquid is reduced.

Also, the bottom of the filling area (10) can be locally hydrophobized, in particular in the vicinity of the venting trench (7), in order to prevent the passage of aqueous sample liquid into the trench (7).

In particular, the capillary stop (16) is advantageously completely hydrophobicized in order to improve the capillary stop and / or retention function of the capillary stop.

Since the film (6) covers these structures, it is advantageously hydrophobically coated in these functional regions.

This can be done, for example, by locally printing the film with a hydrophobic coating in these subregions.

The local coating, in particular spotting, with hydrophilic coatings is preferably provided in fluid-conducting areas such as the discharge channel (9), the analysis chambers (20) and the first deaeration channel (22).

A coating with a hydrophobic or hydrophilic film contributes functionally in these areas to a better and advantageously complete, largely air bubble-free and largely complete filling of these structures (9, 20, 22).

The film is at least locally provided with an adhesive layer, in particular adhesive layer. Preferably, both film surfaces are at least partially provided with an adhesive layer, so that by means of the film both the Cartridge base (2) and the cover element (3) are joined.

During the joining process, a first cover film is first removed from the film (6) so that a first adhesive layer is exposed. Then the Cartridgebasis (2) and the film (6) are positioned to each other and glued to the open adhesive surface.

After bonding, a second cover film is peeled off from the film (6), the pasted cartridge base (2) is positioned relative to the cover element (3), and the cartridge base (2) is connected to the cover element (2) via the film (6).
In the cover element (3), the membrane (14) is welded in advance centrally.
As a product results in the cartridge (21) according to the lower illustration in FIG. 1 comprising a separation device (1) according to the present invention.

As an alternative to the double-sided adhesive film used, provision may be made to use an adhesive-layer-free film (6).
This may advantageously be a film (6) which has on one side at least locally a sealing layer.

During cartridge production, the film (6) is laminated by means of the sealing layer.
For this purpose, the film with the sealing layer on the Cartridgebasis (2) is positioned, thermally fused the sealing layer and a fluid-tight connection between the Cartridge base (2) and film (6).

Alternatively, the film can also be applied in particular by a cold laminating method, wherein in particular an acrylate adhesive layer is used for joining.

If a laminating film (6) is used, it may be advantageous to weld the cover element, fasten it to the cartridge base via a riveted joint, or to provide another double-sided adhesive film for fastening the cover element to the laminating film.

Advantageously, the cover element has a trough (5). This assists the addition of sample liquid through its funnel-shaped form, which receives the added fluid in the trough area and feeds the filling opening (15).

Particularly advantageously, the trough (5) is formed approximately to the attachment surface (18), in particular the funnel depth of the trough (5) corresponds approximately to the vertical distance between the attachment surface (18), the membrane (14) and the surface of the cover element (3 ).

This structural design of the trough (5) ensures a direct fluid drainage of sample liquid discharged onto the trough surface into the membrane region.

The hopper depth is advantageously 0.5 millimeters to 10 millimeters.

Particularly advantageously, the trough is circular or elliptical, wherein the radius of the long side of the particular elliptical trough (5) should be 1 to 1.5 centimeters and the radius of the short side 0.7 to 1 zenith.

The radius of a circular trough (5) should be in particular 1 to 1.5 centimeters.

In a further second embodiment according to FIG. 2 comprises the lower plate-shaped substrate (2), the base of the cartridge (21) a fluidic network consists of a discharge channel (9) and an analysis chamber (20) vented through channels (13).
The channel (9) centrally receives separated sample fluid from an inlet chamber (10).
The inlet chamber (10) is vented through a circumferential trench via channels (19).

According to the second embodiment FIG. 2 is the upper plate-shaped substrate (3), the lid member (3), shown with the underside.

The cover element (3) has a recess around the filling opening (15) with a fastening surface (18). In this recess, a membrane (14) is inserted centrally, in particular thermally connected to the mounting surface (18).

The film (6) is a laminating film which is laminated on the lower plate-shaped substrate (2).

After joining the membrane (14) in the recess of the upper plate-shaped substrate (3) of this cover element is positioned with the separation region to the opening (15) in the film and adhered to the film.

Instead of gluing alternative joining processes such as ultrasonic welding or riveting can be used.

It would also be conceivable to hold the components firmly to each other by a further, not shown, outer housing or to clamp, for example by hold-down and / or positioning means and / or elastic holding means in the outer housing.

The film (6) comprises a filling opening (15) into which a tongue-shaped film part protrudes.

In FIG. 7 a cross section through such a joined sample separation is shown. Here is the FIG. 7 a cross section at the level of the tongue (8).

Again FIG. 7 is to be taken to the second embodiment, covers the tongue (8) the channel (9) in the outer region of the inlet chamber (10), so that in the outer region of the inlet chamber (10) no flow of sample liquid from the inlet chamber (20) into the channel (9).

In the assembled state, the membrane (14) is at least partially on the tongue (8).

In the execution after the FIGS. 7 to 9 advantageously fills the membrane (14) completely. The membrane rests on the cover (8) and the bottom of the inlet chamber (10), so that the membrane (14) surrounds the cover (8). Particularly advantageously, the inlet chamber (10) is filled approximately completely by the membrane (14), so that the dead volume in the chamber approaches zero.

The dead volume of the inlet chamber is understood to mean the volume in the inlet chamber which lies between the lower boundary surface of the membrane (14), the separating surface (17) and the chamber bottom of the inlet chamber and has a capillary action on the fluid. In particular, this capillary action is created by gaps remaining between the membrane (14) and the bottom of the inlet chamber and may undesirably retain fluid in the inlet chamber through capillary action.

Also, the volume of the membrane (14) can at least partially create dead volume due to the inherent capillary network, since in the capillary channels and capillary pores of the membrane (14) sample liquid is retained capillary.

As the FIGS. 8 and 9 schematically represent, the membrane (14) in the opening region of the central channel (9) preferably on the entire surface of the bottom of the inlet chamber (10).

For sample separation, a sample is introduced into the feed device (4). After the FIGS. 7 to 9 this is a drop of blood.

FIG. 8 and FIG. 9 are sections through the sample separation (1) in the central area of the inlet chamber (10).

How out FIG. 8 can be seen, the blood drop is absorbed through the capillary membrane (14), with larger solid blood particles deposited in the membrane. Due to the hydrostatic fluid pressure of the sample liquid, a fluid drop of separated sample liquid, in this case blood plasma, forms in the membrane, especially centrally in the inlet chamber.

The shape and length of the cover (8), namely the film tongue (8) is selected such that the channel (9) is not covered in the central region of the inlet chamber (10) but is open at the top. The upper boundary surface of the channel (9) is advantageously formed by the underside of the membrane (14). This results in a central opening region of the channel (9) with a small fluid aperture.

As the FIGS. 8 and 9 can thereby be achieved that the separated sample liquid, the blood plasma is taken directly from this channel opening.

The plasma thus flows from the separation membrane (14) via the inlet chamber (10) into the opening of the channel (9) without completely filling the filling chamber (10) during the separation.

Functionally, this has the effect that the plasma to be analyzed is fed directly to the analysis chamber (20).
This direct feed thus contributes to a short analysis time for, for example, an assay since fluid filling times are shortened.

Another functional effect of the sectional channel cover is the reduced dead volume of the membrane (14), since in this arrangement, a direct fluid flow into the channel (9) can be done without complete wetting of the membrane (14) must take place.

With reduced dead volume is thus a higher amount of sample volume, here blood plasma available.

In particular, in investigations of fingerprick blood levels, ie 1 to 50 microliters of blood, the separation amount is a critical size for diagnostic tests, since after the separation of only 5 to 20 microliters of plasma for example antibody reactions are available.

FIG. 4 shows such a sample separation (1) in longitudinal section, wherein the filling region facing downward.

The film (6) covers a discharge channel (9) at least in sections, so that a central opening of the channel (9) remains.

Particularly advantageous is the opening portion of the channel (9), here the channel end provided with a means for discharging the fluid from the chamber into the channel. Particularly preferably, the means is a notch, a transitional profile and in particular a ramp. This ramp (12) reduces the capillary resistance between the channel (9) and the bottom of the inlet chamber (10), so that the wetting of the channel and the inflow of liquid into the channel is improved.

In FIG. 4 the fluid flows of the plasma from the membrane (10) through the filling chamber (10) in the channel (9) are symbolized by arrows.

Separate sample liquid, in the exemplary embodiment blood plasma, can also be transported into the channel (9) from outside areas of the inlet chamber.
This can be achieved, for example, if the channel has a higher capillarity than the inlet chamber (10), or if the plasma is created by applying an overpressure (from the outside) and / or underpressure (to the channel (9)) through the sample separation (1 ) is conveyed into the channel (9) and the further fluidic network.

FIG. 5 illustrates a sample separation according to the first embodiment of FIG. 1 in longitudinal section.

According to this first embodiment, the channel (9) is open within the entire filling chamber (10) and continuously absorbs liquid in its course in the filling chamber.

A perspective view of a sample separation 1 according to the invention is shown in FIG FIG. 6 shown. Here, the membrane (14) is not shown to allow insight into the inlet chamber (10).

Structurally, this embodiment essentially corresponds to the exemplary embodiment according to FIGS Figures 2 . 4 and 7 to 9 ,

LIST OF REFERENCE NUMBERS

1-

sample separation

2

lower plate-shaped substrate

3

upper plate-shaped substrate

4

feeding

5

trough

6

foil

7-

venting trench

8th-

channel cover

9-

channel

10-

plenum

11-

sample

12-

ramp

13-

grave widening

14-

membrane

15

fill opening

16-

capillary

17-

interface

18-

mounting surface

19-

vent channel

20

analysis chamber

21-

cartridge

22-

First venting channel

25

gap

Claims (9)

1. Device for sample separation, particularly for separating blood, comprising
   a lower plate-shaped substrate (2) with channel structures moulded into the substrate (2) and a film (6) arranged on the lower plate-shaped substrate (2), wherein the film (6) covers the channel structures,
   a feed device (4) for vertically receiving the sample (11),
   a separating device (14,15) for separating sample constituents, wherein the separating device (14,15) comprises a vertical opening (15), a filter (14), in particular a membrane (14),
   an inlet chamber (10) for receiving separated sample liquid, particularly blood plasma, said inlet chamber being arranged on the separating device (14,15) and open to fluids from the separating device (14,15), and
   a channel (9) which conveys the separated sample liquid in the lateral direction from the inlet chamber (10), wherein the channel (9) is formed by a recess in the base of the inlet chamber (10), so that the inflow region for the separated liquid is located in the channel (9) in the inlet chamber (10),
   characterised in that
   the film (6) forms a cover which partly covers the channel (9) in fluidtight manner, wherein the cover is constructed as a tongue (8) which is connected in one piece to the film (6) and wherein the tongue (8) projects into a fill opening in the film (6),
   so that the inflow region of the channel (9) is located in the central region of the inlet chamber (10) and is not covered but is open at the top, and
   wherein the lower filter surface forms an upper separating surface towards the inlet chamber, wherein the separating surface (17) in the region of a channel opening abuts on the base of the inlet chamber (10) and wherein the channel (9) extends at least partly under the separating surface (17), so that after flowing through the separating surface (17) sample liquid separated by the separating device is able to wet the channel (9) directly and to flow into the channel (9).
2. Device for sample separation according to one of the preceding claims, characterised in that the inflow region of the channel (9) comprises a means for discharging a fluid, particularly a ramp (12), so that fluid flows from the base of the chamber, particularly over the ramp (12), into the channel (9).
3. Device for sample separation according to one of the preceding claims, characterised in that the feed device (4) comprises a well (5) which is formed in an upper plate-shaped substrate (3).
4. Device for sample separation according to one of claims 1 to 2, characterised in that the feed device (4) comprises an insert which is arranged in interlocking engagement on an upper plate-shaped substrate (3).
5. Device for sample separation according to one of the preceding claims, characterised in that apart from a region in which the channel (9) runs, the inlet chamber is surrounded by a venting trench (7) which forms a capillary stop for sample liquid (11) and laterally limits the inlet chamber.
6. Device for sample separation according to claim 5, characterised in that the venting trench may comprise widened portions (13) at its ends.
7. Device for sample separation according to one of the preceding claims, characterised in that a recess is provided on an upper plate-shaped substrate (3) at the fill opening (15), the recess comprising an attachment surface (18) for a membrane (14).
8. Device for sample separation according to claim 1, characterised in that the film (6) has at least one adhesive layer.
9. Device for sample separation according to one of claims 1 or 8, characterised in that the film (6) at least partly covers a venting trench (7).

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